No machan G is superior than X. if you can compare two of these. you can see that X is lacks with fully automatic Air Conditioner & Teak panels etc. and it doesn't even got Tacho. in 121 Range, Corolla Luxel is the fully loaded version. it's got 1.8L Engine (1ZZFE VVTI) same engine goes with US Version of Corolla.
Check the Luxel
and heres the G Version (It's got the same Aircon controls as Luxel, but check the Gear Shifter)
Check the X (Observe the Aircon controls..)
regarding your first question, No the latest 141 Imported by dealers got the 3ZZ-FE Dual VVTI 1.6L Engine (Don't know about the JDM Model Corolla Axio) and the Older 121 G version got the 1NZ-FE VVTI 1.5L Engine and the Luxel Version Got the 1ZZ-FE VVTI 1.8L (Same As Allion A18) Engine. and some X Versions got 2NZ-FE 1.3L Model Engines too. i herd these are bit underpowered for a Corolla.